info on 4D/240 crunching and compilers

[John McCalpin]

In article <32454 at sgi.SGI.COM> bron at bronze.SGI.COM (Bron Nelson) writes:
>In article <238 at noether.UUCP>, rosalia at noether.UUCP (Mark Galassi) writes:
>> I came across a report that the parallelizing FORTRAN (what was it,
>> power FORTRAN or super FORTRAN or whatever) was kind of flaky,
>> and that the ordinary compilers only worked well without optimization
>> (this is on the 4 processor machine).

>I (and many others) have used the compiler extensively with very little
>problem.  Both the parallelizer and the optimizer work fine.  Several
>hundred thousand lines of code check out.

We have been testing out a 4D/120 and have had reasonable results.
The static load distribution technique is only going to give good
performance in a single-task environment, but that is what the machine
appears to be advertised as, so this is not a problem.

I have not had any trouble with the optimizer, though some others here
have gotten incorrect results out of their codes.

Our conclusion is that the machine is a fine parallel processor for
single parallelizable jobs.  For multiple users, the throughput of
the machine is MUCH higher if all the jobs are compiled and run without
the multi-processing option.

>The best thing to do is to call your nearest SGI office and try to
>arrange to run your code.  The best benchmark is your application.  Don't
>take my word for it; check it out for yourself!

Yup.

>Bron Campbell Nelson >bron at sgi.com  or possibly  ..!ames!sgi!bron
-- 
John D. McCalpin - Dept of Oceanography - Florida State University
mccalpin at masig1.ocean.fsu.edu		mccalpin at nu.cs.fsu.edu
mccalpin at fsu (BITNET or MFENET)		SCRI::MCCALPIN (SPAN)